Conventionally, conditions of a transmission are determined exclusively depending on a signal of an inhibitor switch. Generally, when the inhibitor switch is broken and no signals can be detected, or when the inhibitor switch outputs overlapping signals, the transmission is determined to be broken. Due to the broken inhibitor switch, the transmission performs control of a limp home, that is, holding the gearshift lever in the third shift range.
In hybrid vehicles, which have relatively complex power trains which generate torque in various components to be provided to a driving wheel, it is required that safe control is performed by determining conditions of the transmission more accurately, thus, more practical and stable countermeasures to correct the inhibitor switch should be developed.